On Sat, Apr 8, 2023 at 7:43 PM
Duncan Brown <[email protected]>
wrote:
>Low-level signalling! There is another variable and reason you
can't put
>TX & RX all on one loop.
On 08-Apr-23 21:04, Nick England wrote:
Normal low-level connection was with the keyboard
feeding one of two inputs to the printer.
At first, I didn't understand Nick's statement.
But then I realized it is another Army/Navy, Kleinschmidt/Teletype
Corp. difference.
A M28 KSR/ASR always had a an ESU with a local loop and a line relay
for isolation from the line. So you could have a low level "loop"
feeding the M28 and then the ESU converted the low level to high
level to feed the selector magnets.
Kleinschmidt machines never included a isolating line relay. Except
at the large comm centers, they normally connected directly to a
wire line modem or FSK converter. A low-level TX signalling
connection was made directly to to the crypto equipment which would
typically be only a few away. There was no low-level signalling on
the RX side from the crypto gear. From the 1950s through the 1980s,
crypto gear was KW-9 (until mid 1960s), KW-7, & KW-26.